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Location:
Brisbane
Registered:
May 2002
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Re: 18RC leaded or unleaded?
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Mon, 07 April 2003 23:55
 
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This thread seems to pop up once a fortnight, but I'll go over it again...
Back in the good old days, lead existed in petrol for two separate reasons:
1. Anti-VSR (valve seat recession) agent.
2. Octane booster.
Note that a tiny amount of lead is required for 1, so most of the lead was actually for 2 as it's a cheap and very effective octane booster.
Now, in the mid-70's Japan switched to unleaded fuel (as did most of the developed world), so ever since then Japanese engines have been designed to run without lead in the fuel - that means they have hardened exhaust valve seats. People in this country assume that anything built before 1986 (when unleaded was introduced here) can't handle unleaded fuel, but that only applies to local engines; almost anything else, including the humble 18R-C, is designed for unleaded fuel.
So while it's true the 18R-C doesn't need lead, the other issue to consider is octane. Leaded fuel used to be 96 RON, but regular ULP is only 91 RON. That's why some engines complain when you chuck unleaded in them - it's nothing to do with the lead, it's the low octane which is causing the problem! Of course that's an easy fix - just fill it up with premium and everything is OK again.
I hope that all makes sense. Can this be made into a tech article, if one doesn't already exist?
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| | Subject | Poster | Date |
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18RC leaded or unleaded?
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FNK11Y | Mon, 07 April 2003 21:00 |
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Re: 18RC leaded or unleaded?
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ra23celicachick | Mon, 07 April 2003 22:36 |
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Re: 18RC leaded or unleaded?
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Jason | Mon, 07 April 2003 23:41 |
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Re: 18RC leaded or unleaded?
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Norbie | Mon, 07 April 2003 23:55 |
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Re: 18RC leaded or unleaded?
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gianttomato | Mon, 07 April 2003 23:59 |
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Re: 18RC leaded or unleaded?
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FNK11Y | Tue, 08 April 2003 01:28 |
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Re: 18RC leaded or unleaded?
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ra23celicachick | Tue, 08 April 2003 01:51 |
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Re: 18RC leaded or unleaded?
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Fattony | Tue, 08 April 2003 08:33 |
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Re: 18RC leaded or unleaded?
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GIN51E | Tue, 08 April 2003 10:52 |
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Re: 18RC leaded or unleaded?
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eastie | Tue, 08 April 2003 11:11 |
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Re: 18RC leaded or unleaded?
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Norbie | Tue, 08 April 2003 13:09 |
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Re: 18RC leaded or unleaded?
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Bugman | Tue, 08 April 2003 13:33 |
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Re: 18RC leaded or unleaded?
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ra23celicachick | Tue, 08 April 2003 22:38 |
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Re: 18RC leaded or unleaded?
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CuRtana | Tue, 08 April 2003 23:21 |
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Re: 18RC leaded or unleaded?
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Norbie | Wed, 09 April 2003 00:58 |
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Re: 18RC leaded or unleaded?
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CuRtana | Wed, 09 April 2003 04:27 |
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Re: 18RC leaded or unleaded?
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eastie | Wed, 09 April 2003 09:54 |
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Re: 18RC leaded or unleaded?
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GIN51E | Wed, 09 April 2003 11:16 |
